A surround sound system typically has a plurality of speaker units arranged around an audience. In a simple surround sound system, such as those used for home entertainment, the speakers may be arranged in a 5.1 speaker configuration consisting of a front left speaker unit, front right speaker unit, rear left speaker unit, rear right speaker unit, a centre speaker unit and a subwoofer. Each speaker unit may include one or more drivers. A driver refers to a single electroacoustic transducer for producing sound in response to an electrical audio input signal from an audio source. The audio source (e.g. a CD, DVD, Blu-ray or digital media content player) may provide different audio signals for different audio channels, where the audio signal for each channel is transmitted to a different speaker unit for generating sound represented by the signal.
In more sophisticated surround sound systems, such as those used in cinemas, there will typically be a larger number of speaker units surrounding the audience. The audio source may provide audio signals for a greater number of audio channels, where the audio signal for each channel may be transmitted to a set of one or more adjacent speaker units located in a particular region relative to the audience for generating sound represented by the signal. By having more speakers generating sound based on the audio signal for different audio channels, the audience is better able to perceive sounds originating from different locations around the audience, thus providing the audience with a more realistic and immersive entertainment experience.
To further enhance the audience's entertainment experience, some surround sound systems include one or more speaker units positioned above the audience for reproducing sound based on audio signals for a height channel. For example, the audio signals for a height channel may represent sounds from objects located above the audience's current perspective in a particular scene, such as the sound of a helicopter flying above the audience. However, there are problems with this approach. Surround sound systems that require one or more speakers on the roof are complicated to setup. For example, it may be complicated or impractical to install one or more speaker units and wiring on the roof of a room or structure, especially in home entertainment environments where there may be a lower ceiling height. After the speaker units are installed, it can be difficult to move the speakers to a different location (e.g. to a different room, or to a new position in the same room to suit a different setup configuration).
Solutions have been proposed to help avoid the use of roof-mounted speakers in a home entertainment environment. In one example, as shown in FIG. 1, upward firing speakers 100 and forward firing speakers 102 are placed adjacent to a television display 104. The speakers 100 and 102 may be separate speaker units (e.g. the upward firing speakers 100 may form part of a sound bar, and the forward firing speakers 102 may form part of floor sitting speaker units), or alternatively, the speakers 100 and 102 may be integrated together as a single speaker unit. The upward firing speakers 102 generate sound based on audio signals from a height channel, and directs the sound to travel along path 106 (i.e. towards a predetermined location 108 (e.g. a part of the roof) located above the listener 110, which is then reflected towards the listener 110). The forward firing speakers 100 generate sound 112 based on audio signals from other audio channels, and direct the sound to travel along path 112 directly towards the listener 110. A problem with this approach is that the height channel typically covers a wide spectrum of audible frequencies, and some of these frequencies (particularly the lower frequencies) lack directivity. This means only some of the sounds (of certain frequencies) will be directed towards the listener 110 after reflection off location 108, while sounds of other frequencies may not be properly directed towards the listener 100 and thus the listener 100 will perceive such sounds to be fainter than sounds properly directed towards the listener 100. Accordingly, the listener 110 will have difficulty hearing some of the sounds originating from the upward firing speakers 100, which may be drowned out by direct sounds originating from the forward firing speakers 102. Consequently, the listener's entertainment experience will be diminished.
An object of the present invention is to provide a system and method to help address one or more of the above identified problems.